- Siglo Veinte Mine (Siglo XX Mine; Llallagua Mine; Catavi), Llallagua, Rafael Bustillo Province, Potosi Department, Bolivia
- Thumbnail, 1.5 x 1.2 x 1.1 cm
Here we have a remarkable, very well crystallized, rich blue color, rare specimen consisting of radiating crystal aggregates of Vauxite. This piece is from the type locality for this material which was discovered along the Contacto and San Jose veins in this mine and was first described by Sam Gordon and Mark Bandy. It is rare to find specimens of Vauxite with such rich color that are not coated by micro Quartz or have a dull grey overtone.